串口发送一个特别的问题
我想的是：首先发Y，看是否读到P，若成功，则后面发P、U、F，分别将值读出。然后，再发Y，周而复始，
若中途或一开始发Y，读不到P，则连续发十次，再收不到则报警。
还请指点。
Dim binP As Boolean '电源通信是否握手成功，则接着发后面的..Dim Varp2, Varp3 As String '判断串口能否收到S 电源是否在线'我用了二个定时器，一个发“Y”，另一个，初始关闭，待确认电源在线后，再打开，发送后面的.Private Sub Form_Load() MyCom1 MSComm2 ‘调用串口 timer2.enabled=flase '2号定时器不能用 Varp2 = "S"End Sub'向电源发送握手信息Private Sub Timer5_Timer() MSComm2.Output = "Y"End Sub'串口事件Private Sub MSComm2_OnComm() Call Sleep(50) '延时 If MSComm2.CommEvent = 2 Then MSComm2.RThreshold = 20 Dim i For i = 1 To MSComm2.InBufferCount SwichVar1 i ’将不定长的数据一个个接起来 buffer1 = buffer1 & Hex(InByte(i)) Next i Varp3 = HexToStr(buffer1)'将收到的转成STR Text1.Text = Varp3 '此处是监测点 End If If StrComp(Varp2, Varp3, vbBinaryCompare) = 0 Then '若相同 POWER1Alarm.FillColor = QBColor(10) ‘灯变绿 binP = True '变量为真 Timer1.Enabled = False '关闭1号定时器 Timer6.Enabled = True '打开2号定时器 Else UPS1Alarm.FillColor = QBColor(12) binADDRS = False Timer6.Enabled = False End If 若不加这一段，则发送没有问题，若我后面发“P”，读出的值也就是“150”功率，此值也就不等于“S”。这时，程序就停了，好像这里有点乱。 （ If temp = 1 Then Varp3 = HexToStr(buffer1) Text2.Text = Varp3 '监测点二 End If ） buffer1 = "" MSComm2.RThreshold = 1 End Sub'向电源发送读命令Private Sub Timer6_Timer() If binADDRS = True Then temp = temp + 1 If temp = 1 Then MSComm2.Output = "P" '读功率值 ElseIf temp = 2 Then MSComm2.Output = "U" '读电压值 ElseIf temp = 3 Then MSComm2.Output = "f" '读频率值 End If If temp > 3 Then temp = 0 End IfEnd Sub
Public Status As BooleanDim Smsg(2) As StringDim msgNext As BytePrivate Sub Form_Load()MSComm1.PortOpen = TrueStatus = FalseSmsg(0) = "P"Smsg(1) = "U"Smsg(2) = "F"'msgNext = 0End SubPrivate Sub MSComm1_OnComm() Dim tmp Dim curr As Byte tmp = MSComm1.Input If tmp = "S" Then Status = True msgNext = 0 'Exit Sub Else 'If Status Then Select Case msgNext Case 0 Text1.Text = Text1.Text & Smsg(msgNext) & " = " & (tmp) Case 1 Text1.Text = Text1.Text & ", " & Smsg(msgNext) & " = " & (tmp) Case 2 Text1.Text = Text1.Text & ", " & Smsg(msgNext) & " = " & (tmp) & vbCrLf End Select msgNext = msgNext + 1 If msgNext = 3 Then msgNext = 0 Status = False End If End IfEnd SubPrivate Sub Timer1_Timer() If Not Status Then MSComm1.Output = "Y" msgNext = 0 Else Select Case msgNext Case 0 MSComm1.Output = Smsg(msgNext) Case 1 MSComm1.Output = Smsg(msgNext) Case 2 MSComm1.Output = Smsg(msgNext) 'Status = False End Select End If 'Timer1.Enabled = FalseEnd Sub
